Protein kinases represent a large family of enzymes, which catalyze the phosphorylation of target protein substrates. The phosphorylation is usually a transfer reaction of a phosphate group from ATP to the protein substrate. Common points of attachment for the phosphate group to the protein substrate include, for example, a tyrosine, serine or threonine residue. Examples of kinases in the protein kinase family include, without limitation, Abl1 (v-Abl Abelson murine leukemia viral oncogene homolog 1), Akt, Alk, Bcr-Abl1, Blk, Brk, Btk, c-Kit, c-Met, c-Src, c-Fms, CDK1-10, b-Raf, c-Raf1, CSF1R, CSK, EGFR, ErbB2, ErbB3, ErbB4, Erk, FGFR1, FGFR2, FGFR3, FGFR4, FGFR5, Flt-1, Fps, Frk, Jak, KDR, MEK, PDGFR, PIK, PKC, PYK2, Ros, Tie, Tie2, and Zap70. Due to their activity in numerous cellular processes, protein kinases have emerged as important therapeutic targets.
ALK (Anaplastic Lymphoma Kinase) is a 1620 amino acid transmembrane protein, consisting of extracellular domain with amino-terminal signal peptide, intracellular domain with a juxtamembranous segment harboring a binding site for insulin receptor substrate-1, and a carboxy-terminal kinase domain. ALK is a member of the insulin receptor tyrosine kinases. Echinoderm microtubule-associated protein-like 4 (EML4) is a 120 KDa cytoplasmic protein, which involves in the formation of microtubules and microtubule binding protein. EML4-ALK is a novel fusion gene arising from an inversion on the short arm of chromosome 2 that joined exons 1-13 of EML4 to exons 20-29 of ALK. The presence of EML4-ALK fusion is identified in approximately 3-13% of NSCLC (non-small cell lung cancer) patients.
To this end, attempts have been made to identify small molecules which act as protein kinases inhibitors. For example, amino heteroaryl compounds diaryl ureas (PCT WO2004/076412) have been described as ALK/c-MET inhibitors.
Epidermal growth factor (EGF) is a widely distributed growth factor that in cancer, can stimulate cancer-cell proliferation, block apoptosis, activate invasion and metastasis, and stimulate angiogenesis (Citri, et al., Nat. Rev. Mol. Cell. Biol. 7:505, 2006; Hynes, et al., Nat. Rev. Cancer 5:341, 2005). The EGF receptor (EGFR or ErbB) is a transmembrane, tyrosine kinase receptor that belongs to a family of four related receptors. The majority of human epithelial cancers are marked by functional activation of growth factors and receptors of this family (Ciardiello, et al., New Eng. J. Med. 358: 1160, 2008) so that EGF and EGFR are natural targets for cancer therapy. The human epidermal growth factor receptor (HER) tyrosine kinase family consists of four structurally related cellular receptors: the epidermal growth factor receptor (EGFR; HER1), HER2 (ErbB2), HER3 (ErbB3), and HER4.
Thus, the compounds that can inhibit protein kinases such as ALK, ROS1, or EGFR kinases activity together can be used to treat human diseases such as cancers.